CVE-2023-32955
📋 TL;DR
This CVE describes an OS command injection vulnerability in Synology Router Manager's DHCP client functionality. Attackers with man-in-the-middle position can execute arbitrary commands on affected routers. All Synology routers running vulnerable SRM versions are affected.
💻 Affected Systems
- Synology Router Manager (SRM)
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete router compromise allowing attacker to intercept all network traffic, install persistent backdoors, pivot to internal network devices, and potentially brick the router.
Likely Case
Router compromise leading to network traffic interception, DNS hijacking, credential theft, and installation of malware on connected devices.
If Mitigated
Limited impact if network segmentation prevents lateral movement and external access to router management is restricted.
🎯 Exploit Status
Requires man-in-the-middle position on network, but no authentication needed. Specific exploit vectors are unspecified in advisory.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: SRM 1.2.5-8227-6 or SRM 1.3.1-9346-3
Vendor Advisory: https://www.synology.com/en-global/security/advisory/Synology_SA_22_25
Restart Required: Yes
Instructions:
1. Log into Synology Router Manager web interface. 2. Navigate to Control Panel > Update & Restore. 3. Check for updates. 4. Install SRM 1.2.5-8227-6 or SRM 1.3.1-9346-3. 5. Reboot router after update completes.
🔧 Temporary Workarounds
Disable DHCP client functionality
allIf router is not acting as DHCP client (e.g., using static IP or different DHCP server), disable DHCP client to remove attack vector.
Network segmentation
allIsolate router management interface on separate VLAN with strict access controls.
🧯 If You Can't Patch
- Implement strict network segmentation to isolate router from untrusted networks
- Deploy network monitoring for unusual DHCP traffic patterns and command execution attempts
🔍 How to Verify
Check if Vulnerable:
Check SRM version in Control Panel > Info Center > DSM/SRM Version. If version is earlier than 1.2.5-8227-6 (for 1.2.x) or earlier than 1.3.1-9346-3 (for 1.3.x), system is vulnerable.Check Version:
ssh admin@router 'cat /etc.defaults/VERSION' or check web interface Control Panel > Info CenterVerify Fix Applied:
Verify SRM version shows 1.2.5-8227-6 or higher (for 1.2.x) OR 1.3.1-9346-3 or higher (for 1.3.x) after update.📡 Detection & Monitoring
Log Indicators:
- Unusual DHCP client activity
- Unexpected command execution in system logs
- Failed authentication attempts to router services
Network Indicators:
- Abnormal DHCP traffic patterns
- Unexpected outbound connections from router
- DNS queries to suspicious domains from router
SIEM Query:
source="synology-router" AND (event_type="command_execution" OR dhcp_anomaly=true)